When you configure either an Oracle ODBC DSN or an OLE DB connection, you must have the Oracle SQL*Net client-side components installed. SQL*Net is the Oracle network transport layer. Most Oracle ODBC drivers, including the Microsoft driver and the Microsoft OLE DB Oracle provider map, call directly to this SQL*Net layer.
After SQL*Net is configured, notice your SQL*Net connection string. Typically, this consists of a specifier for the Oracle database server name and the network protocol type (such as TCP/IP and named pipes). Often, the SQL*Net connection string is mapped to an alias. In this case, it is only necessary to note the alias. For information about how to configure SQL*Net, contact your Oracle DBA, refer to the SQL*Net documentation, or refer to your Oracle ODBC driver Help file for an example of a connection string.